Bluetooth (BT) and wireless local area network (WLAN) in the 2.4 GHz industrial, scientific and medical (ISM) band share the same unlicensed frequency medium. As the two technologies are developed under different standard bodies, the coordination of BT/WLAN for avoiding interference has become important and been attempted in many domains including frequency, power, and time afterwards. Frequency domain techniques include adaptive frequency hopping (AFH), and power domain techniques include power back-off or de-boosting. Time domain techniques include some form of frame alignment. The actual implementation of these techniques is difficult because they require close coordination between the two wireless technologies. Further, active interference cancellation (AIC) has been investigated, but prior AIC implementations have various limitations in case of wideband interference due to group delay and frequency selectivity of the wideband coupling channel.
As many communication devices, especially handheld devices, are equipped with both BT and WLAN, the coordination between the two technologies has become more important. Therefore, coexistence solutions to enable concurrent transmission and reception are desirable. For instance, when a device is transmitting on BT while receiving on WLAN, the received WLAN signal can be de-sensed due to high self-interference caused by the close proximity of the BT transmitter. In the case where the device is transmitting on WLAN while receiving on BT, similar interference problem can occur. Interference coordination between WLAN signal and BT signal has become more important because many BT traffic is delay sensitive (e.g., phone call or audio streaming), and WLAN is being used for voice traffic (e.g., VOIP). Thus, novel coordination techniques for BT and WLAN coexistence taking into consideration of signal prioritization are greatly desired.